From 6b5462ec433d217ce0fb19d3e51fd86ce48bd031 Mon Sep 17 00:00:00 2001
From: Brad Hards <bradh@frogmouth.net>
Date: Sun, 26 Feb 2017 07:12:06 +1100
Subject: [PATCH] [Timeline] Modify redraw logic to treat scroll as needing
 restack. (#2774)

This addresses #1982 and #1417.

It possibly reduces performance, but correctness seems better.
---
 lib/timeline/component/ItemSet.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/timeline/component/ItemSet.js b/lib/timeline/component/ItemSet.js
index 972db387..695602e8 100644
--- a/lib/timeline/component/ItemSet.js
+++ b/lib/timeline/component/ItemSet.js
@@ -616,8 +616,10 @@ ItemSet.prototype.redraw = function() {
   // TODO: would be nicer to get this as a trigger from Range
   var visibleInterval = range.end - range.start;
   var zoomed = (visibleInterval != this.lastVisibleInterval) || (this.props.width != this.props.lastWidth);
-  if (zoomed) this.stackDirty = true;
+  var scrolled = range.start != this.lastRangeStart;
+  if (zoomed || scrolled) this.stackDirty = true;
   this.lastVisibleInterval = visibleInterval;
+  this.lastRangeStart = range.start;
   this.props.lastWidth = this.props.width;
 
   var restack = this.stackDirty;